Exactly six months ago, Eric Schmidt made a remark that in the near future, developers might want to focus on Android first, instead of iOS. While developers haven't moved to Android-first, iOS-later en masse, there's no denying that we're seeing more and more former iOS exclusives move towards Android.

You can do some things in Android and make those work on most mobile phones and tablets if you use the SDK which is Java based.

Being Java based you can do only cute twitter apps, facebook apps, calendars, chess games and other apps with low hardware requirements.

Any more serious apps requires being native. And Android doesn't encourage native apps and it doesn't provide lots of useful apis. More than that, you have to recompile and fine tune your native app for every goddam ARM chip used in a phone or in a tablet.

There isn't an ARM ABI and an app compiled for a Broadcom chip (as in Raspberry Pi) won't run on a Samsung chip, the app compiled for a Samsung chip won't run neither on a Nvidia chip nor on a TI Snapdragon chip, nor on another Samsung chip.